Why does my material seem 'pixelated'?
Glass cup not pixelated, but a lot of noise, which caused by small amount of samples.

It can be reduced in viewport with OptiX viewport denoiser in Render tab (OptiX avaible only on RTX cards):



at render with  View layer denoising:



or after render with Intel Open Image Denoiser node in Compositor (Denoising Data should be checked in View Layer):



And the last, the scale of blender layouts could be customized by holding Ctrl + Middle mouse button pressed with moving mouse Up and Down